We propose to develop methods whereby direct measures of norephinephrine (NE), dopamine (DA), and serotonin (5-HT) metabolism by brain in awake animals can be determined. Using this methodology we propose to determine the degree to which CNS amine metabolism contributes to the quantities of NE, DA, and 5-HT metabolites found in plasma and urine. Ultimately the information derived from these studies may be used to study amine metabolism in psychiatric patients. In addition we propose to investigate the possibility that noradrenergic receptor sensitivity is different in depressed patients as compared to normal comparison subjects.